Beyond Bitcoin: Your Guide to Digital Currencies via @mashable

Each currency brings something slightly different to the table, but there are a few overlapping characteristics: Each is a system in itself, some almost completely closed while others mesh into the wider global economy. Each offers an answer to the problems that issue from the current troubled economic times. And each seems both unlikely to succeed, and part of an inevitable movement to include created currencies in the world's economy. Think of digital currency as an Esperanto that people are actually beginning to speak.